[WIP] add "auto" attr in notifications

public/platform/modules/notifications/WebNotificationData.h

Index: public/platform/modules/notifications/WebNotificationData.h
diff --git a/public/platform/modules/notifications/WebNotificationData.h b/public/platform/modules/notifications/WebNotificationData.h
index c1f0a5370e8b88e615303b0725622b379dc1cfc3..b1785aa889f634261f0fca1a48f4492df3c5375f 100644
--- a/public/platform/modules/notifications/WebNotificationData.h
+++ b/public/platform/modules/notifications/WebNotificationData.h
@@ -14,11 +14,12 @@ namespace blink {
 struct WebNotificationData {
     enum Direction {
         DirectionLeftToRight,
-        DirectionRightToLeft
+        DirectionRightToLeft,
+        DirectionAuto
     };
 
     WebNotificationData()
-        : direction(DirectionLeftToRight)
+        : direction(DirectionAuto)
         , silent(false)
     {
     }